AURORA, CO (RNN) - On Sunday, President Barack Obama visited the families and victims of the shooting at a premiere of The Dark Knight Rises offering support and condolences, then spoke to the nation with a press conference.

"To the entire community of Aurora, the country is thinking of you," he said.

This came just before a planned candlelight vigil held Sunday night in remembrance of those lost.

The vigil was focused on the lives of victims and the heroic efforts of bystanders and first responders who helped the injured instead of the horrific shooting itself. During the vigil, the names of each of the 12 deceased were called out, with the crowd answering "I will remember."

Earlier in the day, a federal law enforcement officer told the Associated Press witness accounts and evidence at the scene showed a rifle with a high-capacity magazine had jammed on the scene.

"One of the guns used in Friday's mass shooting at a premiere of The Dark Night Rises jammed, potentially keeping the massacre from claiming more lives."

James Eagan Holmes, the man accused of shooting which claimed 12 lives and injured 58 others, will make his first court appearance Monday.

Holmes threw tear gas at an Aurora, CO, showing of the movie before shooting indiscriminately into the theater.

The massacre has been called the largest mass shooting in U.S. history.

Police Chief: Evidence of 'calculation and deliberation'

Holmes had a high volume of packages delivered to his home in the weeks before the attack, which Aurora Police Chief Dan Oates said he believed was evidence of "calculation and deliberation" by the suspect.

"We think this begins to explain how he got his hands on all of the magazines and the ammunition that we talked about yesterday," Oates said. "We also think it begins to explain some of the materials he had in his apartment."

At the 4 p.m. ET news conference Saturday, Oates would not talk about possible motives for the shooting. However, he said the FBI behavioral analysis unit was "plugged in" to the investigation, and they would be working together to figure out Holmes' motivation.

"Whatever we find out in that arena, we will present that in court," Oates said.

Police detonate explosives found in Holmes apartment

An FBI spokesman gave specifics about the explosives authorities found inside the apartment Holmes lived in.

Special agent Jim Yacone said multiple bombs had been "rendered safe" using robot bomb technicians and other tools. He said an extensive amount of evidence had been collected.

"The threat has not been completely eliminated," Yacone said. "It has been significantly reduced."

He said they found IEDs filled with unknown substances which they treated as "accelerant," along with triggering mechanisms such as wires and fuses.

"Once we got rid of that first booby trap, which was really a wire across the front door, we then had to neutralize a hyperbolic mixture - a form of an oxidizer and some fuel that we saw immediately inside," Yacone said.

Oates said bomb experts were expected to finish the scene Saturday evening, with nearby residents expected to return Sunday.

The theater where the shooting took place could be reopened Monday or Tuesday.

Aurora Mayor Steve Hogan and Colorado Gov. John Hickenlooper met with some of the victims at area hospitals Saturday. They both thanked first responders and others who helped during the emergency.

"There's no way we can turn the clock back, there's no way we can reverse what has happened," Hickenlooper said. "But we can take this aberrant, inconceivable event and do everything we can to make it better."

An Aurora police spokeswoman had updated reporters through the day as the explosive experts made progress.

"We have been successful in disabling a second triggering device," said Sgt. Cassidee Carlson with the Aurora Police Department. "Although not certain, we are hopeful that we have eliminated the remaining major threats. However, we will not know this until we have entered the apartment."

Via Twitter, police stated other hazards remain inside. They expected to be on location for hours collecting evidence and dealing with any other dangers.

"In the event that more triggering devices are found, there is a possibility of more controlled disruptions to occur," they announced.

Police performed a controlled explosion of one of the bombs found inside the home Saturday. Aurora police announced the detonation was successful.

CNN reported a booming noise come out of the home. Authorities on scene yelled "fire in the hole" before it happened.

No fire or large amounts of smoke could be seen afterward.

Bomb specialists had already defeated another explosive inside the home.

"We have been successful in defeating the first threat," Carlson said.

During the 12:30 p.m. ET news conference, Carlson said a tripwire had been set to cause a fatal detonation when someone entered the apartment. With that device out of the way, the team began "reassessing the scene."

"There are other devices inside," she said.

Also, the team may have to do a controlled detonation on some of the other bombs inside. Carlson said a reverse 911 call would be sent out if they were forced to do that.

Police had to navigate a ‘web of wires'

Carlson held a prior conference at 10:10 a.m. ET Saturday, when she explained what authorities faced inside the home.

"The most immediate threat is the tripwire, the booby trap we have been talking about over the last day," Carlson said. "Once that situation is mitigated - that may cause a controlled detonation that may cause a loud boom - from that, there may also be a fire that erupts at that point.

"We have [Aurora Fire Department] on standby ready to handle any situation that occurs."

Authorities then would move on to disposal of other explosives, which could be taken off-site.

"We are confident in our evacuations at this point," Carlson said. "Those buildings that have been evacuated, they remain as such. We are confident this is a safe area now with the evacuations in place. If that changes, we will immediately address those issues."

She added authorities would be careful to not destroy any possible evidence related to the shooting investigation. FBI, ATF and other national specialists have joined local and area departments to assist.

Before the detonation of the initial trip wire, officials had said possible explosive and chemical devices inside the suspect's home prevented them from safely entering. They included bottles filled with unknown liquids, what appeared to be mortar rounds and jars of bullets.

A "web of wires" was set to trip the devices, according to the report.

The Denver Post stated surrounding buildings were evacuated when authorities confirmed the apartment had apparent IEDs inside. Holmes reportedly told police his home had been rigged to explode when they detained him after the shooting.

Loud techno music began to play at the apartment early Friday, around the time the murders took place, according to Denver Post. A neighbor told reporters she found the door ajar when she went to ask Holmes to turn it down, but she did not go inside.

On Saturday, Dr. Bob Snyder with the Medical Center of Aurora said four patients remained in the hospital's ICU. Of those four, two were in critical but stable condition.

"There is going to be some realization that there are going to be serious long-term issues that people are going to have to deal with," Snyder said. "We have staff in place, as far as mental health counselors, to work with the patients and their families. We are going on a case-by-case basis to address their needs as best we can."

Police Chief: ‘We are not looking for any other suspects'

Police said Holmes, 24, legally purchased the four weapons he used, as well as 6,000 rounds of ammunition on the internet, in the last 60 days.

He's the lone suspect in the murders at the midnight premiere of The Dark Knight Rises.

"We are not looking for any other suspects," Oates said. "We are confident that he acted alone. However, we will do a thorough investigation to be absolutely sure that is the case, but at this time, we are confident he acted alone."

As of Friday evening, 30 people remained in area hospitals, 11 in critical condition.

"It's an act that defies description," Hickenlooper said.

Holmes reportedly had recently withdrawn from a Ph. D. program the University of Colorado Denver.

At his undergrad alma mater, the University of California Riverside, where he graduated with honors, Chancellor Timothy P. White said "People are trying to digest the news."

"Academically, he was at the top of the top. He distinguished himself from an academic point of view during his four years with us," White said.

Oates said police detained the suspect shortly after they received "hundreds of calls" at 2:39 a.m. ET Friday.

"Mister Holmes was apprehended outside his white Hyundai parked in the back of the theater, and he was apprehended with three weapons in the car," Oates said. "One was left at the scene inside the theater."

An AR-15 assault rifle, a Remington 12-gauge shotgun and a two .40 caliber Glock handguns were the weapons police found.

Two of the victims died at hospitals, while the other 10 bodies remained at the scene much of Friday.

Oates said the last of the bodies had been removed as of 5 p.m. local time and police would begin the process of identifying them and notifying loved ones.

Among the victims were three servicemen, according to the Department of Defense. Two of them were killed.

Oates also confirmed their belief the shooter used gas grenades to disorient the crowd before he opened fire into the movie's audience in Theater 9.

Holmes' family in California expressed sadness for the tragedy caused by the alleged actions of the suspect.

"Our hearts go out to those who were involved in this tragedy and to the families and friends of those involved," Holmes' family said in a statement released by San Diego police.

The family is cooperating with police in California and Colorado, and there is nothing to suggest family members had any involvement with the shooting, according to San Diego Police spokesperson Lt. Andra Brown.

Hickenlooper called the fatal shootings "senseless" and the act of a deranged mind.

"We need to recognize that we can't allow people that are aberrations of nature to take away the joys and freedoms that we enjoy," Hickenlooper said.

At the press conference Friday, he said words could not express the intensity of the tragedy.

"Our hearts are broken as we think about the family and friends of the victims," Hickenlooper said.

He added both he and Hogan received a phone call from Obama. Hogan also spoke, calling it "a tragic day for this community and this city."

"But as tragic as it is for the community and the city, it is an absolute horror for all of those people who were in those theaters and their families," Hogan said. "Our hearts go out to them. We will always wish - no matter how much we do now - that we had done more."

Victims included six children, 3-month-old

Initial reports indicated 14 people had died, however an official statement downgraded the death toll to 12.

"I didn't realize something was wrong right away," one witness told KUSA. "I thought it was a firecracker or a firework or something. I thought someone was like 'it's the Batman premiere, I'm going to bring some firecrackers in, throw it, get people riled up.'

"But it wasn't until the alarm sounded saying there's an emergency in the building, [I realized] something's going on. That's when I figured it was something serious."

The victims range from infants to 45 years old. CNN reported six of them had been taken to children's hospitals.

Dr. Comilla Sasson at the University of Colorado Hospital said one of the youngest victims, a 3-month-old child, had been discharged from care.

USA Today reported on Twitter the infant had not been shot and was taken to the hospital only as a precaution.

Frank Lansville, a spokesman for Aurora Medical Center, said they received 15 patients from the incident. He said five of them were in critical condition, and a total of six would have surgery.

Lansville said none of the victims at AMC had died, and eight had been released.

Obama, Romney condemn incident as ‘evil'

Both candidates for president put politics aside Friday. Mitt Romney spoke about the shooting before a crowd in Bow, NH.

"Our hearts break with the sadness of this unspeakable tragedy," Romney said. "Ann and I join the president, first lady and all Americans in offering our deepest condolences for those whose lives were shattered in a few moments of evil in Colorado.

"I stand before you today not as a man running for office, but as a father and grandfather, a husband, an American."

He suggested people offer comfort to someone near who is suffering or heavy-laden, as well as mourn with those in Colorado.

Obama canceled campaign activities for the day after hearing of the shooting. He did show at a planned stop in Fort Myers, FL, to speak about it.

Obama offered condolences to the people affected, asked everyone to keep Aurora in their thoughts and prayers and held a moment of silence for those lost. He said the day was a reminder how "all of us are united as one American family."

"Life is very fragile," he said. "Our time here is limited and precious. What matters at the end of the day is not the small things. Ultimately, its how we treat one another and love one another. It's what we do on a daily basis that gives our lives meaning and what gives our lives purpose."

He added the federal government stood ready to do whatever was necessary to bring the person responsible to justice.

Shooter used gas to stun moviegoers and was well-armed

Holmes, a North Aurora resident, reportedly wore body armor and a gas mask. Law enforcement officials said the gunman went to the back door of the theater, propped it open, "geared up" and threw a smoke bomb or tear gas grenade, according to CNN.

He then began to shoot indiscriminately into the crowd, according to witnesses.

Aurora Police Public Information Officer Frank Fania reported witnesses said the gunman "just appeared," tossed a canister of some type, there was a hissing noise and then smoke filled the theater, possibly tear gas, before he opened fire.

"Somebody kicked in the emergency exit and started throwing gas grenades and started shooting people at random," said one person who claimed to be in the theater. "At first, it took me a second to realize what was actually going on. And as people were running away I hit the ground so I wouldn't be hit.

"I heard the sound of metal canisters clinking around, and then I saw plumes of smoke."

Shooting witness Jennifer Seeger told The Today Show the gunman fired at people as they were trying to go for the exit doors. According to her, he started shooting while at the corner of the screen then continued shooting as he made his way to the top of the stairs and back down toward the front.

"He was about five feet away from me on my right side," Seeger said. "I was sitting on the second row on the very front. He came in and threw in the gas can, and at that point I knew it was real. He shot at the ceiling and then pointed the gun right at me. At that point I dove into the aisle.

"He started shooting people behind me, and the bullets started falling on my head. [They were] burning my head because they were so fresh."

Tracy Weise, the spokesperson for the Medical Center of Aurora, said walk-in victims to the hospital were treated for gas inhalation. The patients were "decontaminated," meaning doctors cleansed the gas from the patients' eyes and skin.

Police took the suspect into custody behind the theater where his car was parked. He did not resist arrest. A bomb squad robot was brought to the scene to investigate the vehicle.

Authorities first received reports of the shooting at 2:39 a.m. ET. The police station is located two to three blocks from the theater, and witnesses said the response was immediate.

Fania said police were grabbing victims and transporting them to the hospital in their police vehicles.

"There were at least four or five individuals that I saw that were actually bleeding from different areas," a mortician who helped first responders told KMGH. "One person was shot in the back in the lower buttocks area, one person was in the arm, another in the leg. It was pretty traumatic.

"I took about five or 10 minutes helping a lady get blood off her face and her body - she was covered in it. I guess, apparently her boyfriend had sustained injuries in the theater."

Another witness told KUSA that he heard anywhere from 10 to 20 shots, then some small explosions and screaming. He said the public announcement system came on, instructing everyone to get out of the theater, and the fire alarm was pulled.

An explosive device was found in a theater, and there were two reports of explosives found in the parking lot.

Witnesses in the theater were bussed away from the scene for interviews with police at a local high school.

One eye witness said they thought it was part of the movie. Another at an area hospital told CNN she saw an infant come into the ER covered in blood.

Police are calling it "a mass tactical incident." Officials set up two command posts in the area: one at a Dillard's department store and the other at Gateway High School.

The FBI told CNN the shooting is not connected to any terrorist group.

Officials at Warner Bros. expressed they were "deeply saddened" by the news. The studio canceled the Paris premiere for the film, as well as interviews scheduled with director Christopher Nolan, star Christian Bale and other cast members.

Aurora is about 20 miles from Columbine, CO, where in 1999 Eric Harris and Dylan Klebold opened fire in Columbine High School. The two killed 12 students and one teacher and injured 21 others.

Copyright 2012 Raycom News Network. All rights reserved.

WALB Online Poll

Should theaters across the U.S. cancel showings of the new Batman movie, 'The Dark Knight Rises?'

Yes, this is a time for reflection and prayer.

Yes, and all movies should be canceled for a few days

No, but theaters should add security.

No, but theaters should stop having midnight premieres.

Thank you for participating in our poll. Here are the results so far:

Yes, this is a time for reflection and prayer.

16%

1454 votes

Yes, and all movies should be canceled for a few days

6%

542 votes

No, but theaters should add security.

62%

5665 votes

No, but theaters should stop having midnight premieres.

16%

1501 votes

Video Clip: RAW: Aerial video of Batman theater shooting - Police say 14 people were killed in a shooting at a late-night showing of "The Dark Knight Rises" at a theater in Aurora, CO near Denver.